PQE Group offers a wide range of Commissioning, Qualification & Validation (CQV) services to ensure that your manufacturing processes are efficient, reliable, and meet regulatory authority standards. Our cutting-edge, integrated approach ensures that all tools used in your manufacturing processes have a significant impact on product quality.
Particle Counting
Contamination is a real risk even for established pharmaceutical companies with highly trained personnel and state-of-the-art equipment. Without proper monitoring and safety measures in place for clean utilities, even tiny amounts of dust, dew point, oil, non-viable particles, and moisture can come into contact with compressed air, which may then come into direct contact with surfaces and components, compromising sterility in the process. This is why continuously monitoring and assessing physical and microbial contamination risks is non-negotiable when it comes to air purity.
Particle counting is one method, based on international regulations used in GMP environments to monitor particulates and assess contamination risks in compressed air and clean utilities. Using this method, manufacturers can identify the number of particles with specific sizes and ensure that the system meets the required standards of purity and cleanliness. Identifying particles is not simply a routine check; it is critical in GMP environments, where inadequate monitoring of physical and microbial contamination can compromise the integrity, quality, and sterility of a product.
Regulatory Foundations & Global Alignment
There is no single harmonized regulation that governs the use of compressed air in GMP environments; however, pharmacopoeia requirements and ISO standards such as ISO 8573-1, along with guidance including ISPE, define compressed air quality expectations in modern pharmaceutical manufacturing.
It is worth noting that although pharmacopoeia requirements are not always explicit when it comes to compressed air systems, they establish clear expectations when air is used in direct contact with products. The European Pharmacopoeia, for example, defines “medicinal air” as compressed ambient air with strict limits on contaminants such as carbon monoxide, carbon dioxide, oil, water, and nitrogen oxides, as well as defined oxygen content. From these specifications, and similar ones found in other pharmacopoeias, it is evident that there is a common principle: gases that come into contact with products must be controlled to a level that ensures they do not compromise product quality by introducing contamination. This creates a risk-based expectation, where compressed air used as a clean utility must be treated in a similar manner to other critical utilities, meaning its quality, use, and quantity must be continuously justified.
While not a regulation, ISO 8573, as an internationally recognized standard, establishes expectations by providing a clear and structured framework to define, measure, and control contamination in compressed air systems. Instead of taking a one-size-fits-all approach, the standard classifies compressed air based on the nature of contaminants, namely solids, dew point, and oil, and assigns purity classes that define allowable limits for each. For manufacturers, this classification system removes ambiguity and allows them to set the required air quality based on the intended application. The standard is not limited to classification alone; it also contains complementary parts that define validated test methods for measuring these contaminants, such as particle concentration and microbiological content. This enables manufacturers not only to specify air quality but also to verify it through consistent and reliable testing.
Although mentioned earlier, it is important to highlight that ISPE guidance expects compressed air used as a clean utility to be managed with the same level of control and oversight as other critical utilities due to its direct impact on product safety and quality. The guidance emphasizes the importance of robust control strategies, ongoing risk assessment, and continuous verification, as utilities such as compressed air, due to their “hidden nature,” are often overlooked. In alignment with ISO standards, ISPE also highlights the importance of risk-based approaches when defining critical quality attributes and control parameters. In addition, it expects strong data integrity practices and periodic system reviews to demonstrate that the system remains in a state of control over time. Overall, ISPE positions compressed air not as a background utility but as a critical system that must be actively managed and continuously justified within a GMP environment.
Compressed Air Regulation in GMP Environments
Since there is no single set of regulations that governs the use of compressed air in GMP environments, pharmacopoeias, ISO standards, and ISPE guidance are used as complementary references, with each addressing different aspects of compressed air quality. While pharmacopoeias define limits for certain contaminants such as oil and gases, ISO 8573 provides a more structured approach with classifications for particles, dew point, and oil. ISPE guidance, on the other hand, offers practical, risk-based recommendations tailored to pharmaceutical manufacturing contexts, bridging the gap between regulatory expectations and real-world implementation.
The Importance of Constant Testing and Monitoring
To ensure that compressed air is consistently meeting GMP expectations requires more than just periodic checks. Structured testing, monitoring, and compliance strategies are needed in addition to technologies such as qualified instrumentation and robust data practices. Using instruments such as particle counters to measure non-viable particles, in combination with multi-gas analyzers and dew point sensors to monitor moisture levels, helps provide manufacturers with a comprehensive understanding of air quality across all critical contamination risks. When used in combination with oil testing and properly calibrated equipment with traceable certification, obtaining accurate and reliable audit-ready data becomes possible.
When it comes to compliance and common shortfalls regarding compressed air, more often than not the issues have less to do with the technology itself and more with how it is implemented and managed over its lifecycle. The quality of compressed air is influenced by several factors including the maintenance of the system itself, system design, and the compressor itself. Both oil and oil-free compressors carry risks; however, oil-lubricated compressors have a higher risk of oil contamination. Although oil-free compressors reduce this risk, they still require proper maintenance to avoid introducing particles or microbial contamination into the system through wear and tear.
Even when air is clean at the point of generation, poorly designed or aging pipework can undermine it by introducing particles. In addition to this, corrosion, stagnant sections, and inadequate drainage points can create conditions where moisture and microbial contamination can accumulate. This makes the distribution system equally critical to maintaining compressed air quality as the compressor and filters. While routine testing and instrument calibration are necessary, they should be carried out in combination with other maintenance activities such as compressor servicing, filter replacement, and line integrity checks. To ensure traceability and consistent system performance throughout the equipment lifecycle, these activities should only be carried out by personnel with the necessary know-how and experience.
Thus, to avoid common contamination risks and maintain product integrity, it is necessary to routinely conduct checks and perform proper equipment maintenance to ensure patient safety.
Technical solutions alone are not enough to address these challenges. What’s needed is a partner who understands regulatory requirements, operational realities, and the importance of proactive system management. That’s where PQE Group makes a difference.
Our global expertise and experience in the life sciences, built on decades of commitment to quality and compliance, enable us to support manufacturers with end-to-end solutions that ensure compressed air systems remain consistently controlled, compliant, and aligned with GMP expectations.
With our global presence and qualified experts, we support our clients throughout the full lifecycle of compressed air quality management, from risk-based strategy definition and on-site testing execution to documentation, data integrity, and audit readiness.
